Technical Field
This application relates to techniques used in connection with storage devices.
Description of Related Art
Systems may include different resources used by one or more host processors. Resources and host processors in a system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as those included in the data storage systems manufactured by EMC Corporation. These data storage systems may be coupled to one or more servers or host processors and provide storage services to each host processor. Multiple data storage systems from one or more different vendors may be connected and may provide common data storage for one or more host processors in a computer system.
A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.
Host processor systems may store and retrieve data using a storage system containing a plurality of host interface units, storage devices such as disk drives and solid state drives, and disk interface units. The host systems access the storage devices through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and the storage device provides data to the host systems also through the channels. The host systems do not address the physical storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units, or more generally logical storage units. The logical storage units may or may not correspond to the actual physical storage drives. Allowing multiple host systems to access a single storage system allows the host systems to share data stored on storage devices of the storage system. In order to facilitate sharing of the data on the storage devices, additional software on the data storage systems may also be used.